Multiple-triode vacuum tube



May 31, 1927. 1,630,443

' F. s. MGCULLOUGH MULTIPLE TRIODE vacuum TUB-E Filed March 15. 1923 WITNESSES:

ATTORNEY Patented May 31; 1927.

' UNITED STATES PATENT OFFICE.

mnamoxs. :u'ocULLoueH, or wrm'imsnune, \PENNSYLVANIA, assre'noa 'ro wnsrmenousa nmcrnrc a manumc'ruame oommny, a coaronarrou or 2mm- SYL'VAN'IA.

MULTIPLE-maroon vacuum TUBE.

My invention relates to thermionic deviee's"-- or hot cathode devices, particularly to a novel arrangement of the electrodes of such devices.

8 Broadly speaking, the ob]ect of my invention is to provide a construction .of thermionic devices or hot cathode devices wh ch will permit the utilization of a plurality of anode elements with a single cathode in a 10 single tube. More specifically, the ob ect of my'mvention' is to construct a 'novel cathode for thermionic emission devices with which a plu-' rality of anode structures may be employed,

either for the purpose of passing a larger current through the device or for the purpose of utilizing a single device in place of a number of tubes such as triodes in the' operationof a number of circuits.

In" previous thermionic devices, the current which could be passed through the device at a given applie voltage, electronemissivity and grid potentialhas been determined bythe space-charge between the cathode and the anode, which, in turn. de-

pends upon the distance between them.

When attempts have been made to increase the current by placing the electrodes closer together. a limit has soon been reached because of structural difliculties.

Also, in previous devices only a single set of circuits has been usable with a given tube device, because of the fact that only a single anode structure or anode and grid structure could be employed.

In carrying my invention into efi'ect. I attach to the cathode a plurality of radial plates or vanes which serve as shields dividing the electron stream into a plurality of 40 separate segments. Each segment may then be provided with its own individual anode structure. or with an anode and control electrode structure. I prefer to utilize an indirectly heated cathode, such as is disclosed in the application of Freeman & Wade, SerialNo. 611.263, filed Jan. 8. 1923, and assigned to the Westinghouse Electric and Manufacturing Company, because of the greater ease of attachment of radial plates to the indirectly heated cathode.

Other objects andconstructional details of my invention will be apparent from the following description and claims when read in connection with the accompanying drawings, wherein Figure 1 is a perspective view of a thermionic device embodying m invention, parts being broken away, and

"Figs. 2 and 3 are diagrammatic views of 'circuits utilizing my thermionic device.

In the drawings is shown a tube havin a cathode 1 which is preferably compose of a cylinder which may be of nickel, latinum, tungsten or other suitable meta and is preferably oxide coated to increase the' electron emission. The cathode 1, in the construction shown, is indirectly heated by a filament or heater element 2, which may be of tungsten, platinum, molybdenum or other suitable material, contained in an electrically insulating support which serves to conduct the heat fromthe filament 2 to the cathode cylinder 1. The support may be of zirconia or other suitable refractor material. The filament is provided wit lead wires 4 which are sealed into a press 5 which also carries a supporting wire-6 for the cathode structure.

According to my present invention, 1 provide the cylindrical cathode 1 with a plu-' rality of electrically conductin radial vanes or plates 7 which have relatlvely low electron emissivity and which may be 243-.

cured to the cathode by welding, riveting, or other convenient means.

an anode 8 and grid 9 fulfilling the custom-.

ary functions of such structures in standard triode tubes. The respective anodes 8 are supported by individual lead wires 11- sealed into the press 5 and the grids 9 are likewise supported by. similar lead wires 12, also sealed into the press 5.

The operation of the device depends upon the fact that the vanes or shields constitute,

As shown in B5 the drawing, the plates 7 are shaped with y in effect, auxiliary control electrodes exerting a controlling efiect upon the spacecharge between: anode and cathode. The space-charge is reducedby reason of the grounding of the vanes on the cathode, and

f hence the space. current flowing under given conditions of cathode temperature and em1ssivity, electrode spacing and plate voltage is increased.

The vanes also divide the electron stream "into independent portions which may be independently controlled, as shown in Fig.

.3. Alternatively, all of the anodeplate and grid structures may be connected together, astshown 1n Fig. 2, either inside or outslde of the tube, 1n which case the greater value .of. each individual electron stream in each sector as compared to the value of the electron stream in an equal sector without the vanes or shields allows a substantially larger current to be passed through the tube, which. results in a tube having not only a large current-carryingcapacity but also a low impedance. In the system illustrated in Fig. 3, the

grid and anode plat-e. structures are kept electrically separate and are connected to distinct sets of circuits, in which case-the single tube will function in a manner similar to a group of tubes which have had their cathodes electrically connected, as is done in supplying a group of tubes from a single A battery, and their grid and anode plate structures connected in separate sets of circuits, as is done in cascade amplification systems.

While I have shown only two systems and one tube structure in the accompanying drawin it is obvious that my invention is suscepti 1e of various changes and modifications without departing from the s irit and scope thereof, It is. desired, there ore,

,that only such modifications and limitations be placed thereon as are .set .forth in the .-prior art or in the appended claims.

I claim as my invention:

1. A vacuum tube having a single cathode, a plurality of anodes and means therewithin for exerting a combined mechanical and electrical action to substantially segregate the space discharges between the oathode and the respective anodes.

2. In ,a space-discharge device, a cathode, a plurality of anodes, a plurality of grids associated therewith, a single container --therefor and means in said container for vmechanically and electrically dividing the electrons emitted from said cathode into substantially separate streams associated with the respective anodes and under the control, of the respective grids.

-3. The combination within a space-discharge device of a conducting element disposed in a radial position adjacent to the flow path of the :space discharge and means for maintaining said element at such potential as to repel the main portion of the space discharge.

4. In a space-discharge. device, the combination with an anode and a cathode, of

an auxiliary electrode positionet substam tially convergent with the direction of flow of the space discharge between the anode and the'cathode.

5. In a space-discharge device, the combination with an anode and a cathode, of an auxiliary electrode positioned substantially convergent with the direction of flow of the space discharge between the anode and the cathode, and a conductive connection between said auxiliary electrode and trode at a predetermined potential with respect to one of said'main electrodes.

8. A vacuum-tube device comprising .a cathode, means for exciting the same to an electron-emitting state, an' anode, means for establishing a space, discharge flow between said anode, and said cathode, an auxiliary electrode positioned substantially converent with the direction of flow of the space discharge between the anode and the oathode, means for maintaining said auxiliary electrode at a substantially constant potential, a grid, an enclosingenvelope for said cathode, anode, auxiliary electrode and grid,

andl'a source of variable potentials for said '11 b 9. A space-discharge device comprising a ity of segmental anodes disposed thereabout, and partition members for substantlally segregating the space discharges between the cathode and the respective anodes.

10. A space-discharge device comprising a substantially cylindrical cathode, a plurality of segmental anodes disposed theresubstantially cylindrical cathode, a pluralabout, partition members for substantially I segregating the space discharges between the cathode and the respective anodes, and individual controlling means for said space discharges.

' 11. A space-discharge device comprising, in substance, a cylindrical cathode and a plurality of concentric segmental grid and anode members, and a plurality of conducting vanes each extending in a radial, longigudinal plane between said segmental memers.

12. A space dischar e device comprising, in substance, a cylin rical cathode and a plurality of concentric segmental grid and anode members, a plurallty of conducting vanes each extendingin a radial, longitudinal' plane between said cylindrical members, and a conductive electrical connection between each of said vanes and one of said cylindrical members.

13. A space-discharge device comprising a cylindrical electron-emitting member, a longitudinally extending conducting *vane attached thereto and extending. radially therefr0m,'and anode means disposed thereabout.

14. A space-discharge device comprising a cylindrical electron-emitting member, a

plurality of longitudinally extending conducting vanes of relatively low electronemissivity attached to said cylindrical member and extending radially therefrom, and

anode means disposed substantially in the surface of a cylinder thereabout.

15. A s acedischarge device comprising a cylindrical electron-emitting 'member, a plurality of longitudinally extending con ducting vanes of relatively low electronemissivity attached to said 0 lindrical member and extending-radially t erefrom, a plurality of anode members spaced around said cylindrical member between the plane's of said vanes, and individual space-current controlling means associated with said anode members.

16. A space-discharge de'vicecomprising an' axially disposed heating member, a

lindrical cathode membersurrounding t e heating member and adapted to be mamtained in electron-emitting condition thereby, a plurality of conducting vanes at least at the same potential as the electron emitting member subdividing the space between said member andsaid structures .to produce a plurality of substantially distinct spacecurrent discharges.

18. A space-discharge device comprising an electron emitting member, a plurality of anode structures, and one or more conducting shields subdividing the space between said electron-emitting member and said anode structures into distinct compartments individual to each anode structure.

In testimony whereof,- I have hereunto subscribed myname this 8th day of March, 1923.

. FREDERICK S. McCULLOUGH. 

